The present invention relates to a coil former having an opening extending therethrough for accommodating a core consisting of two shells. The coil former has a winding body with flanges formed on both ends. At least one of the flanges has a connecting ledge extending in the transverse direction relative to the longitudinal axis of the opening. The connecting ledge has at least three soldering terminals arranged side by side for receiving winding wires wound about the winding body.
A known coil former of the above mentioned type has soldering terminals. The terminals are designed as soldering tags and have a substantially rectangular flat cross-section, wherein the width of the cross-section is substantially larger than its height. The ends of winding wires forming the windings on the winding body are wound about the soldering tags. The winding wires are then fixed to the soldering tags by soldering. Because of the high soldering temperature and subsequent cooling, changes in the length of the winding wire occur during this soldering process. These changes in length increase the tensile stress within the winding wire. This may impair the soldering quality and may cause the winding wire to be damaged or torn off during operation under varying work temperatures. Further, with the known coil former, using an automatic winding machine for winding the winding wire about a soldering tag is laborious. This is true since the path along which the winding wire is guided from the winding body to the soldering tag is complicated and the winding wire may be torn off at the edges of the soldering tags if it is pulled tightly.
It is the object of this invention to provide a coil former which permits simple automatic winding and which operates reliably.
This object is solved for a coil former of the above-mentioned type by providing soldering terminals in the form of essentially cylindrical pins embedded into bases such that they protrude vertically from the bases. The bases are spaced apart from one another, and each base has a rounded surface turned towards its associated pin. Each base supports a deflecting means for deflecting the winding wire before it is wound about the pin.
According to the invention, the soldering terminals are designed as essentially cylindrical pins. The cylindrical shape of the pins makes it possible to tightly wind the end of a winding wire about the pin, without any risk of tearing off the winding wire on sharp edges. The pins are embedded into bases which are spaced apart from one another and have a rounded surface. The winding wire can thus easily be supplied to the pin since the wire smoothly slides across the base and does not become entangled even if the coil former has a wrong orientation relative to a winding device. Further, according to the invention a deflecting means is provided for deflecting the winding wire before winding it about the pin. The deflecting means provides strain relief for the winding wire, to compensate for tensile stresses occurring during soldering.
Preferably, the deflecting means is designed as a deflecting peg, extending from the base radially relative to the coil former. This arrangement makes it possible to optimize the movement sequence of the winding device and the coil former relative to each other in a numerically controlled winding machine, since it is sufficient to effect pivotal movements by 90xc2x0. By using a cylindrical deflecting peg, the risk of tearing off the winding wire is reduced even if the winding wire is pulled tightly.
According to an embodiment of the invention, the connecting ledge, on the side facing towards the winding body, supports a wall extending in the longitudinal direction of the coil former. The wall is arranged at a predetermined distance from the bases, thereby creating a space through which the winding wire or winding wires are guided. These measures provide a guiding path for the winding wire or winding wires which ensures that the ends of the winding wires are supplied to the pins without crossing each other.
According to another embodiment of the invention, the wall has a vertically extending spacer. The end of the spacer extends beyond the height of the winding wire wound onto the pin. The spacer establishes a predetermined spacing from the printed board. This ensures that the end of the winding wire wound onto the pin and connected thereto by soldering is arranged at a sufficient distance from through holes in the printed board, to prevent faulty soldering as a result of covered through holes.